There have been many experiments and demonstrations that explain the physics of producing sound, especially musical tones. Some of these experiments and demonstrations include blowing air over the open ends of tubular cavities of varying lengths, changing the tension in a string having a set functional vibrating length, blowing air against a rotating disc having apertures located equiangularly therein, etc.
One of the most popular of such demonstrations is based on experiments conducted by Pythagoras and other ancient Greeks which involved changing the functional vibrating length of a string having a set tension. Pythagoras experimented with a string stretched with a constant tension over a sounding board of a sounding box and supported by a bridge resting on the sounding box. By placing the bridge at various positions along the string, different sounds are perceived when the string is set into vibration.
The ancient Greeks very accurately measured the functional vibrating length of the string, i.e., the distance between the point where the string contacted the bridge and the adjacentmost point where the string was prevented from vibrating, such as a fret contacting the string. The sounds produced by vibrating the string when the bridge is placed at a selected location yielding a first functional vibrating length of the string and thereafter vibrating the string when the bridge is placed at another location yielding a second functional vibrating length were found to have a pleasing relation when the ratio of the first functional vibrating length to the second functional vibrating length was a certain fraction, especially a fraction of small whole numbers, e.g., 2/1, 4/1, 5/2, and 5/3. The Greeks combined sounds having such pleasure relations into a host of scales and composed songs comprising successions of sounds in a certain scale.
The aspect of music theory relating sound to the functional vibrating length of a string having a constant tension may be explained to students with the aid of an instrument similar to that used by the ancient Greeks. To the inventor's knowledge, the bridge used by the ancient Greeks and others prior to the invention disclosed herein comprises a base portion that rests on the sounding board and an apex or top portion supporting, and upon which rests, the stretched string. When instruments with such bridges are used by students, the bridges tend to become disengaged from the strings when the bridges are translated or repositioned along the strings, when the strings are in a non-stretched condition, or when the instrument is subjected to a sudden jolt. Such disengagement causes wasted time in re-engaging and properly positioning the bridges and the strings. Furthermore, such disengagement results in many bridges becoming misplaced or lost.